The present embodiments relate to a rotary anode for an X-ray tube and to a method for producing a base body for such a rotary anode.
X-ray tubes, as are used, by way of example, in medical X-ray equipment, include a cathode, from which electrons are accelerated toward a rotating rotary anode. The rotary anode includes a base body that carries a focal path made of tungsten or a tungsten-rhenium alloy, which forms the actual anode. When sufficiently accelerated electrons strike the focal path, the atoms of the focal path are excited accordingly and, consequently, imitate X-rays at the desired wavelength. Rotation of the rotary anode is intended to keep the thermal stress as low as possible in the process. Since increasingly higher radiation intensities are desired for X-ray tomography, for example, the focal spot of the electrons is to be focused as sharply as possible on the focal path and is to be as small as possible, and this leads to high power densities in the focal spot region and a high temperature development. To compensate this, high rotational speeds of the rotary anode are desired.
Known rotary anodes include a base body made of a titanium-zirconium-molybdenum alloy that has a relatively high density with a relatively low high temperature strength. Owing to the mechanical properties of such base bodies, rotational frequencies of only 200 Hz to 250 Hz may be achieved with current rotary anodes.
Base bodies made of ceramic materials are known in addition to such titanium-zirconium-molybdenum base bodies. Therefore, US 2010 002 7754, by way of example, describes a base body in the form of an anode ring for a rotary anode that is made from graphite or silicon carbide (e.g., see FIG. 1 showing a rotating anode from US 2010 002 7754 having a drive center A, a curved disc B, rigid fit elements C, an anode ring D, small pyrolytic graphite plates E, an x-ray-generating layer F, and slits G). The anode ring also includes radially oriented right-angled chambers, in which the small segments made of pyrolytic carbon may be inserted to dissipate and store the resultant heat as quickly as possible. Combinations made of molybdenum-titanium-zirconium alloys and silicon carbide are known. However, the high rotational frequencies used in modem X-ray equipment may not be achieved with materials of this kind.